The present invention relates to an air bag inflation apparatus and, more particularly, to an aspiration-type air bag inflation apparatus which reduces the inflation rate of the air bag in the event that an occupant of a vehicle impacts the air bag before it is fully inflated.
In a typical automobile collision, air bag inflation is essentially completed at the time an occupant starting from a properly seated position moves forward and contacts the inflated air bag. In this instance, the occupant in moving forward contacts the bag surface at approximately the speed the vehicle had just prior to vehicle impact. The occupant moving into the bag is enveloped and brought to rest by the cushioning effect of the pressurized bag. However, an occupant who is not properly positioned sitting back in the seat, but instead is leaning forward or sitting forward or standing in front of the seat or in contact with the air bag module cover at the time of vehicle impact may interfere with the air bag during the inflation process. In this instance, the bag surface is developing and expanding rearwardly into the vehicle interior at a high velocity relative to the vehicle. The bag intercepts the occupant moving forward in the aforementioned manner producing a relative occupant-air bag surface impact velocity as high as 200 m.p.h. The partially inflating and expanding bag envelopes the occupant, bringing the occupant first to rest relative to the vehicle and then as the bag continues to pressurize, accelerates the portion of the occupant's body in contact with the bag rearward with substantial force, which may result in serious or fatal injury. A need has arisen, therefore, for an air bag inflation apparatus that will automatically mediate the inflation rate of the air bag to limit the pressure developed in the air bag to the level necessary for the safe protection of the occupant regardless of proximity to the air bag module in the vehicle at the time of vehicular impact.